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    <ul class="crumbs"><li><a href="../index.html">Home</a></li><li><a href="../inform7n.html">Inform7</a></li><li><a href="index.html">values</a></li><li><a href="index.html#3">Chapter 3: Literals</a></li><li><b>Literal Version Numbers</b></li></ul></div>
<p class="purpose">To parse version numbers written semver-style.</p>

<p class="commentary firstcommentary"><a id="SP1" class="paragraph-anchor"></a><b>&#167;1. </b>The notable thing about this code is that we could match v4, v5, and so forth,
but choose not to: we want to avoid collisions with variable names innocently
chosen as "v" plus a number. So you need to use at least one dot. "v4.0"
achieves the same effect as "v4" would in any case.
</p>

<pre class="displayed-code all-displayed-code code-font">
<span class="function-syntax">&lt;s-literal-version-number&gt;</span><span class="plain-syntax"> </span><span class="identifier-syntax">internal</span>
<span class="plain-syntax">    </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Wordings::length</span><span class="plain-syntax">(</span><span class="identifier-syntax">W</span><span class="plain-syntax">) != </span><span class="constant-syntax">1</span><span class="plain-syntax">) </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">FALSE</span><span class="plain-syntax">;</span>
<span class="plain-syntax">    </span><span class="identifier-syntax">inchar32_t</span><span class="plain-syntax"> *</span><span class="identifier-syntax">p</span><span class="plain-syntax"> = </span><span class="identifier-syntax">Lexer::word_raw_text</span><span class="plain-syntax">(</span><span class="identifier-syntax">Wordings::first_wn</span><span class="plain-syntax">(</span><span class="identifier-syntax">W</span><span class="plain-syntax">));</span>
<span class="plain-syntax">    </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">p</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">p</span><span class="plain-syntax">[0] == </span><span class="character-syntax">'v'</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax">        </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">segments</span><span class="plain-syntax">[3] = { </span><span class="constant-syntax">0</span><span class="plain-syntax">, </span><span class="constant-syntax">0</span><span class="plain-syntax">, </span><span class="constant-syntax">0</span><span class="plain-syntax"> };</span>
<span class="plain-syntax">        </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">segment_count</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">, </span><span class="identifier-syntax">digits</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">;</span>

<span class="plain-syntax">        </span><span class="reserved-syntax">int</span><span class="plain-syntax"> </span><span class="identifier-syntax">i</span><span class="plain-syntax"> = </span><span class="constant-syntax">1</span><span class="plain-syntax">;</span>
<span class="plain-syntax">        </span><span class="reserved-syntax">while</span><span class="plain-syntax"> (</span><span class="identifier-syntax">p</span><span class="plain-syntax">[</span><span class="identifier-syntax">i</span><span class="plain-syntax">]) {</span>
<span class="plain-syntax">            </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">Characters::isdigit</span><span class="plain-syntax">(</span><span class="identifier-syntax">p</span><span class="plain-syntax">[</span><span class="identifier-syntax">i</span><span class="plain-syntax">])) {</span>
<span class="plain-syntax">                </span><span class="identifier-syntax">segments</span><span class="plain-syntax">[</span><span class="identifier-syntax">segment_count</span><span class="plain-syntax">] = </span><span class="constant-syntax">10</span><span class="plain-syntax">*</span><span class="identifier-syntax">segments</span><span class="plain-syntax">[</span><span class="identifier-syntax">segment_count</span><span class="plain-syntax">] + ((</span><span class="reserved-syntax">int</span><span class="plain-syntax">) </span><span class="identifier-syntax">p</span><span class="plain-syntax">[</span><span class="identifier-syntax">i</span><span class="plain-syntax">] - (</span><span class="reserved-syntax">int</span><span class="plain-syntax">) </span><span class="character-syntax">'0'</span><span class="plain-syntax">);</span>
<span class="plain-syntax">                </span><span class="identifier-syntax">digits</span><span class="plain-syntax">++;</span>
<span class="plain-syntax">                </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">digits</span><span class="plain-syntax"> &gt; </span><span class="constant-syntax">9</span><span class="plain-syntax">) {</span>
<span class="plain-syntax">                    ==&gt; { </span><span class="identifier-syntax">fail</span><span class="plain-syntax"> </span><span class="identifier-syntax">nonterminal</span><span class="plain-syntax"> };</span>
<span class="plain-syntax">                }</span>
<span class="plain-syntax">            } </span><span class="reserved-syntax">else</span><span class="plain-syntax"> </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">p</span><span class="plain-syntax">[</span><span class="identifier-syntax">i</span><span class="plain-syntax">] == </span><span class="character-syntax">'.'</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">segment_count</span><span class="plain-syntax"> &lt; </span><span class="constant-syntax">2</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">digits</span><span class="plain-syntax"> &gt; </span><span class="constant-syntax">0</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax">                </span><span class="identifier-syntax">digits</span><span class="plain-syntax"> = </span><span class="constant-syntax">0</span><span class="plain-syntax">; </span><span class="identifier-syntax">segment_count</span><span class="plain-syntax">++;</span>
<span class="plain-syntax">            } </span><span class="reserved-syntax">else</span><span class="plain-syntax"> {</span>
<span class="plain-syntax">                ==&gt; { </span><span class="identifier-syntax">fail</span><span class="plain-syntax"> </span><span class="identifier-syntax">nonterminal</span><span class="plain-syntax"> };</span>
<span class="plain-syntax">            }</span>
<span class="plain-syntax">            </span><span class="identifier-syntax">i</span><span class="plain-syntax">++;</span>
<span class="plain-syntax">        }</span>
<span class="plain-syntax">        </span><span class="reserved-syntax">if</span><span class="plain-syntax"> ((</span><span class="identifier-syntax">digits</span><span class="plain-syntax"> &gt; </span><span class="constant-syntax">0</span><span class="plain-syntax">) &amp;&amp; (</span><span class="identifier-syntax">segment_count</span><span class="plain-syntax"> &gt; </span><span class="constant-syntax">0</span><span class="plain-syntax">)) {</span>
<span class="plain-syntax">            </span><span class="identifier-syntax">TEMPORARY_TEXT</span><span class="plain-syntax">(</span><span class="identifier-syntax">vtext</span><span class="plain-syntax">)</span>
<span class="plain-syntax">            </span><span class="identifier-syntax">WRITE_TO</span><span class="plain-syntax">(</span><span class="identifier-syntax">vtext</span><span class="plain-syntax">, </span><span class="string-syntax">"%d"</span><span class="plain-syntax">, </span><span class="identifier-syntax">segments</span><span class="plain-syntax">[0]);</span>
<span class="plain-syntax">            </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">segment_count</span><span class="plain-syntax"> &gt;= </span><span class="constant-syntax">1</span><span class="plain-syntax">) </span><span class="identifier-syntax">WRITE_TO</span><span class="plain-syntax">(</span><span class="identifier-syntax">vtext</span><span class="plain-syntax">, </span><span class="string-syntax">".%d"</span><span class="plain-syntax">, </span><span class="identifier-syntax">segments</span><span class="plain-syntax">[1]);</span>
<span class="plain-syntax">            </span><span class="reserved-syntax">if</span><span class="plain-syntax"> (</span><span class="identifier-syntax">segment_count</span><span class="plain-syntax"> &gt;= </span><span class="constant-syntax">2</span><span class="plain-syntax">) </span><span class="identifier-syntax">WRITE_TO</span><span class="plain-syntax">(</span><span class="identifier-syntax">vtext</span><span class="plain-syntax">, </span><span class="string-syntax">".%d"</span><span class="plain-syntax">, </span><span class="identifier-syntax">segments</span><span class="plain-syntax">[2]);</span>
<span class="plain-syntax">            </span><span class="identifier-syntax">semantic_version_number</span><span class="plain-syntax"> </span><span class="identifier-syntax">V</span><span class="plain-syntax"> = </span><span class="identifier-syntax">VersionNumbers::from_text</span><span class="plain-syntax">(</span><span class="identifier-syntax">vtext</span><span class="plain-syntax">);</span>
<span class="plain-syntax">            </span><span class="identifier-syntax">DISCARD_TEXT</span><span class="plain-syntax">(</span><span class="identifier-syntax">vtext</span><span class="plain-syntax">)</span>
<span class="plain-syntax">            ==&gt; { -, </span><a href="2-rvl.html#SP14" class="function-link"><span class="function-syntax">Rvalues::from_version</span></a><span class="plain-syntax">(</span><span class="identifier-syntax">V</span><span class="plain-syntax">, </span><span class="identifier-syntax">W</span><span class="plain-syntax">) }</span>
<span class="plain-syntax">            </span><span class="reserved-syntax">return</span><span class="plain-syntax"> </span><span class="identifier-syntax">TRUE</span><span class="plain-syntax">;</span>
<span class="plain-syntax">        }</span>
<span class="plain-syntax">    }</span>
<span class="plain-syntax">    ==&gt; { </span><span class="identifier-syntax">fail</span><span class="plain-syntax"> </span><span class="identifier-syntax">nonterminal</span><span class="plain-syntax"> };</span>
<span class="plain-syntax">}</span>
</pre>
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